Passenger oxygen

[usp3r]

I have heard that the oxygenmasks in the cabin are not used if there is smoke present. But why is that? Wouldn´t it be better to get smooky air mixed with oxygen than just smooky air?

Is it because the increased fire hazard that oxygen creates that one choose not to use it?

[FakePilot]

It's my understanding that all the oxygen mask does is mix pure O2 in with outside air. So if smoke etc were present you'd still inhale it, albeit with more oxygen.

Don't take my word over an expert's, though :)

[Sheep Guts]

Id say that your last comment is the most correct Usp3r. Oxygen is major part the fire traingle , heat and fuel being the other critical indgredients. Once smoke has been detected in the Cabin the Crew Dons masks establishes communication deals with enviromentals Packs off and aircond systems off usually, simultaneously commencing an emergency decent for that very reason that the Pax masks (rubber jungle)shouldnt be deployed.These Pax Oxy masks arent regulated and are resultant of a chemical reaction, different to Crew Oxy which is tank Oxygen with demend regulators and masks.
Also during this decent, the Cabin staff are finding the source of the smoke and fighting the fire as necessary. Once at 10000 ft or MEA most drills require venting the Cabin with crew window open etc.Ofcourse the vital part is to land ASAP. Fire especially in Cargo hold is the most dangerous as it is usually an unknown entity.So landing and evacuating is all thats one the crews mind.

Ofcourse there are other ways to do this, but this is the way I was taught. Open to constructive criticism.

Sheep